Pressure sensitive record sheets employing indole- and carbazole-subtituted phthalides



Nov. 17, 1970 CHAD-HAN LIN 3,540,910 PRESSURE SENSITIVE RECORD SHEETSEMPLOYING INDOLE- AND CARBAZOLE-SUBSTITUTED PHTHALIDES Original FiledJan. 30, 1967 BASE- SHEET OF RECORD MATERIAL COATED ON THE REAR WITHMINUTE PRESSURE- RUPTURABLE CAPSULES CONTAINING LIQUID SOLUTION OFCHROMOGENIC MATERIAL DEVELOPABLE ON CONTACT WITH AN ELECTRON- ACCEPTINGMATERIAL OF THE LEWIS- ACID TYPE TO COLORED FORM RECEIVING SURFACE OFUNDERSHEET COATED WITH AN ELECTRON- ACCEPTING MATERIAL OF THE LEWIS-ACIDTYPE I I A. axzazawamssssmuaws:

INVENTOR CHAO- HAN LIN finited States Patent Olfice 3,540,910 PatentedNov. 17, 1970 3,540,910 PRESSURE SENSITIVE RECORD SHEETS EM- PLOYINGINDOLE- AND CARBAZOLE-SUB- TITUTED PHTHALIDES Chao-Han Lin, Dayton,Ohio, assignor to The National Cash Register Company, Dayton, Ohio, acorporation of Maryland Original application Jan. 30, 1967, Ser. No.612,369, now Patent No. 3,491,111, dated Jan. 20, 1970. Divided and thisapplication Jan. 24, 1969, Ser. No. 817,596

Int. Cl. B41m /22 U.S. C]. 11736.2 46 Claims ABSTRACT OF THE DISCLOSUREA pressure sensitive record unit and method of marking, employingchromogenic material of normally colorless form having a structuralformula:

where CN1 and CN2 consist of mono and disubstituted indolyl radicalshaving the structural formula:

and carbazolyl radicals having the structural formula:

where R R and R consist of alkyl radicals having from one to four carbonatoms, aryl radicals, and hydrogen; and Where Y and Z consist ofhydrogen and dialkylamino radicals where the alkyl substituents havefrom one to four carbon atoms, providing that one of Y and Z must behydrogen and the other must be said dialkylamino radical.

Specific examples are 3,3-bis-(l,2-dimethylindol-3-yl)-5-dimethylaminophthalide and 3,3-bis-(1,2-dimethylindol-3-yl)-6-dimethylaminophthalide.

This is a division of application Ser. No. 612,369, filed Jan. 30, 1967,now U.S. Pat. No. 3,491,111.

This invention pertains to novel chromogenic compounds for use inpressure sensitive record material and to an improved mark-formingmanifold system incorporating these novel chromogenic compounds. Morespecifically, this invention pertains to 3,3-di-aryldialkylaminophthalides which have the form of substantially colorless,i.e. white, or slightly colored solids, or approach being colorless whenin liquid solution, but which may be converted to dark-colored formsupon reactive contact with acidic material. As used in mark-formingsystems, marking in desired areas on support webs or sheets may beaccomplished by eifecting localized reactive contact between thechromogenic material and the acidic material on or in such web or sheet,such material being brought thereto by transfer, or originally there insitu, the desired reactive contact forming dark-colored materials in theintended image-marking areas.

Pressure-sensitive, mark-forming systems of the prior art include thatdisclosed in application for Letters Pat. No. 392,404, filed Aug. 27,1964, by Robert E. Miller and Paul S. Phillips, Jr., now abandoned. Thelatter application provides a marking system of disposing on and/ orwithin sheet support material the unreacted markforming components (atleast one of which is a polymeric material) and a liquid solvent inwhich each of the mark-forming components is soluble, said liquidsolvent being present in such form that it is maintained isolated by apressure-rupturable barrier from at least one of the mark-formingcomponents until the application of pressure causes a breach or ruptureof the barrier in the area delineated by the pressure pattern. Themarkforming components thereby are brought into reactive contact,producing a distinctive mark.

It is an object of this invention to provide new and improved substanceshaving chromogenic properties which may be incorporated in a web orcoated onto the surface of a web to provide a novel manifolding unit,and which are useful in carrying out improved methods of markinginvolving reactive contact with a color-activating material to developdark-colored materials in areas where marking is desired.

It is an object of this invention to provide modified compounds, basedupon di-aryl dialkylaminophthalide derivatives, which are substantiallycolorless, or slightly colored offering a new and improved variety ofchromogenic characteristics, and developing novel dark-coloredsubstances upon contact with color-activating materials.

It is a further object of this invention to provide a new and improvedmark-forming system which has the form of disposing within a web or uponthe surface of a web or sheet support material unreacted chromogenicmaterial which is capable of being reactively contacted with an acidicmaterial to produce a dark-colored substance, thus providing markshaving desirable color intensity and hue.

In accordance with this invention, there are provided novel,substantially colorless or slightly colored, chromogenie compoundshaving the structural formula:

where consist of mono and disubstituted indolyl radicals having thestructural formula:

Rrf

and carbazolyl radicals having the structural formula:

a '2 Ito 2 1 CH CH3 1 N 3 1 N i 4 I CH3 1 cm (CHa)zN-'3,3-bis-(1,2-dimethylindol 3 yl) 6 dimethylaminophthalide having thestructural formula:

1 4 o=o CH3 CHa 3,3-bis-(9-ethylcarbazo1 3 yl) 5 dimethylamino-3,3-bis-(9-ethylcarbazol-3-yl) 6 dimethylaminophthalide having thestructural formula:

3,3 bis (2 phenylindol 3 -yl) 5 dimethylaminophthalide (CITa) 2-N 4 3,3bis (2 phenylindol 3 yl) 6 dimethylaminophthalide n I 3 a o 2 2 i 1 N N4 c H I l H H N(CH3)2 3,3 bis (1 methyl 2 phenylindol 3 yl 5dimethylaminophthalide 3,3 bis (1 methyl 2 phenylindol 3 yl) 6dimethylaminophthalide 3 (1,2 dirnethylindol 3 yl) 3 (9 ethylcarbazol-3-yl -5-dimethylaminophthalide 3 (1,2 dimethylindol 3 yl) 3 (9ethylcarbazol- 3-yl)-6-dimethylaminophthalide.

I I(CHa)2 In accordance With another feature of this invention, a newcomposition of matter comprises the dark-colored substance having aresonant form developed by contact of a color-activating material Withone of the above-mentioned chromogenic compounds. The color-developingor activating material is an acidic substance for converting thechromogenic compound to the resonant form.

The method of marking of this invention, i.e., by developing adark-colored material from substantially colorless or slightly coloredchromogenic compounds comprises providing a chromogenic compoundselected from among the above-mentioned compounds and bringing suchchromogenic compound into reactive contact in areas where marking isdesired With an acidic color-activating substance to produce adark-colored resonant form of the chromogenic compound by the actionthereon in said areas of the said acidic substance.

The acidic materials employed in this invention can be any compoundWithin the definition of a Lewis acid, ire.

an electron acceptor. Preferably, acidic organic polymers such asphenolic polymers are employed as the acidic material. The novelchromogenic materials exhibit the advantage of improved color stabilitywhen reacted with such phenolic polymers. The solution formation of thesolid particles of polymeric material in the same solvent with thesubstantially colorless chromogenic compounds allows penetration of thecolor into the support sheet, if porous, e.g., paper, so that thecolored form of the chromogenic material sinks into the body of thesheet and is not merely on the surface of the sheet. This featureprotects against erasure of recorded data by attrition of the surface ofthe record sheet.

Reference is to be taken to the drawings. FIG. 1 is a diagrammaticrepresentation of a two-sheet unit manifold, a perspective in which thebottom surface of the overlying is supplied on the surface or near itwith a multiplicity of minute pressure-rupturable microcapsules, eachcontaining a droplet. Each droplet contains a solution of the basicchromogenic compound. An acidic component, such as an acid clay or aphenolic polymeric material lies within the lower web or sheet or uponthe upper surface of the lower web or sheet. A colored mark is made bythe use of a stylus, a type character, or other pressure-writing meansapplied to the two-sheet unit manifold.

The encapsulated droplets are released on the rupture of the capsules inwriting operations, as shown in FIG. 1a. The liquid of the releaseddroplets is transferred in the pattern of the data configuration to thetop of the underlying sheet. The top of the underlying sheet is coatedor impregnated with a material reactant with the chromogenic material,e.g., a phenolic polymer material having an acid-reacting OH group. Thedrawings show capsules on the over sheet containing a liquid solution ofchromogenic material. However, the capsules can contain the polymericphenolic material in liquid solution and the top surface of theunder-sheet may be supplied with the chromogenic material in particulateform. The improvement in the system is the chromogenic compound which isthe novel substance of the instant invention.

Referring again to FIG. 1 comprising an upper web or sheet having thechromogenic material dispersed within or upon in a contiguousjuxtaposition, it is possible to incorporate the chromogenic material ina solid, crystalline-state in a binder material so that the chromogenicmaterial may be transferred from the upper Web or sheet upon theapplication of pressure from a stylus to deposit some of the chromogenicmaterial on a surface carrying a color activating polymeric material.Preferably, the chromogenic substance is dissolved in a solvent andminute droplets of the solution of the chromogenic material areencapsulated in minute, pressure-rupturable capsules. Obviously, manyother arrangements, configurations and relationships of the solvent andthe mark-forming materials, with respect to their encapsulation andlocation on the supporting sheet or webs can be envisioned. Sucharrangements are thoroughly described in the aforementioned applicationS.N. 392,404 to Miller et a1. and need not be repeated herein.

It is noted that the polymeric mark-forming components should have acommon solubility with the chromogenic material in at least one liquidsolvent when the acid-reacting material is a phenolic or other organicacidic polymer. It is also noted that in a single system severalchromogenic materials may be used with the same or different polymericmaterials. Several polymeric materials can be reactively contacted witha single chromogenic compound or with a mixture of chromogeniccompounds.

As mentioned above, the solvent is maintained in physical isolation inminute droplets until such time as it is released by application ofpressure. This may be accomplished by several known techniques, butpreferably isolation is maintained by individual encapsulation of thesolvent droplets in a microcapsule according to the proceduresdescribed, for example, in U.S. Pat. No. 2,712,507, issued to Barrett K.Green on July 5, 1955; 2,730,457 issued to Barrett K. Green and LowellSchleicher on Jan. 10, 1956; 2,800,457, issued to Barrett K. Green andLowell Schleicher on July 23, 1957; and 2,800,458, issued to Barrett K.Green on July 23, 1957, reissued as Re. Pat. No 24,899 on Nov. 29, 1960.The microscopic capsules, when disposed within or upon a supporting webas a multiplicity in contiguous juxtaposition, are rupturable bypressure, such as normal marking pressures utilized, for example, inwriting or typing operations.

The material or materials chosen as the wall material of themicrocapsule, in addition to being pressure ruptura ble, must be inertwith respect to the contents of the capsule and the other mark-formingcomponents so that the wall material remains intact under normal storageconditions until such time as it is released by the application ofmarking pressure. Examples of such wall materials are gelatin, gumarabic and many others thoroughly described in the aforementionedpatents.

For use in record material, the capsule size should not exceed 50microns in diameter. Preferably, the capsules should be smaller than 15microns in diameter.

The acidic polymeric material useful in this invention include phenolicpolymers, phenol acetylene polymers, maleic acid-rosin resins, partiallyor wholly hydrolyzed styrene-maleic anhydride copolymers andethylene-maleic anhydride copolymers, carboxy polymethylene and whollyor partially hydrolyzed vinyl methyl ether maleic anhydride copolymerand mixtures thereof.

Among the phenolic polymers found useful are alkylphenol-acetyleneresins, which are soluble in common organic solvents and possesspermanent fusibility in the absence of being treated by cross-linkingmaterials. A specific group of useful phenolic polymers are members ofthe type commonly referred to as novolacs, (as sold by Union CarbideCorp., New York, NY.) which are characterized by solubility in commonorganic solvents and which are, in the absence of cross-linking agents,permanently fusible. Generally, the phenolic polymer material founduseful in practicing this invention is characterized by the presence offree hydroxyl groups and the absence of groups such as methylol, whichtend to promote infusibility or cross-linking of the polymer, and bytheir solubility in organic solvents and relative insolubility inaqueous media. Again, obviously, mixtures of acidic materials can beemployed.

Resoles, if they are still soluble, may be used, though subject tochange in properties upon aging.

A laboratory method useful in the selection of suitable phenolic resinsis the determination of the infra-red ab sorption pattern. It has beenfound that phenolic resins showing an absorption in the 3200-3500 cm.-region (which is indicative of the free hydroxyl groups) and not havingan absorption in the 1600-1700 cm? region are suitable. The latterabsorption region is indicative of the desensitization of the hydroxylgroups and, consequently, makes such groups unavailable for reactionwith 7 the chromogenic materials.

The preparation of the phenolic formaldehyde polymeric materials forpracticing this invention is described in Industrial and EngineeringChemistry, volume 43, pages 134 to 141, January 1951, and a particularpolymer thereof is described in Example 1 of U.S. Pat. No. 2,052,093,issued to Herbert Honel on Aug. 25, 1936, and the preparation of thephenol-acetylene polymers is described in Industrial and EngineeringChemistry, volume 41, pages 73 to 77, January 1949.

The preparation of the maleic anhydride copolymers is described in theliterature, such as, for example, one of the maleic anhydride vinylcopolymers, as disclosed in the publication, Vinyl and Related Polymers,by Calvin E. Schildknecht, Second printing, published April 1959, byJohn Wiley & Sons, Incorporated. See pages 65 to 68 (styrene-maleicanhydride copolymer), 628 to 630 (vinyl 7 methyl ether-maleic anhydridecopolymer), and 530 to 531 (ethylene-maleic anhydride copolymer).

When the acidic material is one of the aforementioned organic polymers,the liquid solvent chosen must be capable of dissolving the mark-formingcomponents. The solvent may be volatile or nonvolatile, and a single ormultiple component solvent may be used which is wholly or partiallyvolatile. Examples of volatile solvents useful in the afore-describedbasic chromogen-acidic polymer are toluene, petroleum distillate,perchloroethylene, and xylene. Examples of non-volatile solvents arehigh-boiling point petroleum fractions and chlorinated biphenyls.

Generally, the solvent chosen should be capable of dissolving at least0.3%, on a weight basis, of the chromogenic material, and about a 3-5 ona weight basis, of the polymeric material to form an efiicient reaction.How ever, in the preferred system, the solvent should be capable ofdissolving an excess of the polymeric material, so as to provide everyopportunity for utilization of the chromogenic material and, thus, toassure the maximum coloration at a reaction site.

A further criterion of the solvent is that it must not interfere withthe mark-forming reaction. In some instances, the presence of thesolvent may interfere with the mark-forming reaction or diminish theintensity of the mark, in which case the solvent chosen should besufficiently vaporizable to assure its removal from the reaction siteafter having, through solution, brought the markforming components intointimate admixture, so that the mark-forming contact proceeds.

Since the mark-forming reaction requires an intimate mixture of thecomponents to be brought about through solution of said components, oneor more of the markforming components may be dissolved in the isolatedsolvent droplets, the only requirement being that at least one of thecomponents essential to the mark-forming reaction be maintained isolateduntil reactively contacted with the other.

In the usual case, the mark-forming components are so chosen as toproduce a mark upon application of pressure at room temperature todegrees centigrade). However, the present invention includes a system inwhich the solvent component is not liquid at temperatures around roomtemperature but is liquid and in condition for forming solutions atelevated temperatures.

The support member on which the components of the system are disposedmay comprise a single or dual sheet assembly. In the case where allcomponents are disposed on a single sheet, the record material isreferred to as a self-contained system. Where there must be a migrationof the solvent, with or without mark-forming component, from one sheetto another, the record material is referred to as a transfer system.(Such a system may also be referred to as a two-fold system, in that atleast two sheets are required and each sheet includes a component, orcomponents, essential to the mark-forming reaction.) Where a copiousamount of the colored reaction product in liquid form is produced on asurface of one sheet, it may produce a mark by transfer to a secondsheet as a colored mark.

In the preferred case, where microcapsules are employed, they may bepresent in the support material either disposed therethroughout or as acoating thereon, or both. The capsules may :be applied to the sheetmaterial While still dispersed in the liquid vehicles in which they weremanufactured, or, if desired, separated and the separated capsulesthereafter dispersed in a solution of the polymeric component (forinstance grams of water and 53 grams of a 1% aqueous solution ofpolyvinyl methyl ether maleic anhydride) to form a coating compositionin which, because of the inertness of the solution and the capsules,both retain their identity and physical integrity. When this compositionis disposed as a film on the support material and dried, the capsulesare held therein subject to rupture to release the liquid contained.This latter technique, relying on the incompatibility of themicrocapsules and the dispersing medium of the film-forming,mark-forming component, allows for a method of preparing a sensitiverecord coating with the capsules interspersed directly in a dry film ofthe polymeric material as it is laid down from the solution. A furtheralternative is to disperse in a liquid a medium one or more mark-formingcomponents, insoluble therein, and disperse in said medium the insolublemicrocapsules, with the result that all components of the mark-formingsystem may be disposed on or within the support sheet in the oneoperation. Obviously, the several components may be appliedindividually.

The respective amounts of the several components will vary, dependingprimarily upon the nature of the materials and the architecture of therecord material unit. Suitable lower amounts include, in the case of thechromogenic material, about .005 to .075 pound per ream (a ream in thisapplication meaning five hundred (500) sheets of 25" x 38" paper,totalling 3,300 square feet); in the case of the solvent, about 1 to 3pounds per ream; and in the case of the polymer, about /2 pound perream. In all instances, the upper limit is primarily a matter ofeconomic consideration.

In the instance where the mark-forming components are interspersedthroughout a single support sheet material (so-called self-containedunit), the following technique or procedure has been found useful:

The slurry of capsules may be applied to a wet web of paper as it existson the screen of a Fourdrinier paper machine, so as to sink into thepaper web a distance depending on the freeness of the pulp and the watercontent of the web at the point of application.

The capsules may 'be placed directly in the paper or in a support sheet.Not only capsule structures, but films which hold a multitude ofdroplets for local release in an area subject to pressure may beutilized. (See US. Pat. No. 2,299,694, which issued Oct. 20, 1942 to B.K. Green.)

With respect to the acidic organic polymeric component, a solutionthereof in an evaporable solvent is introduced into twice as much waterand agitated while the evaporable solvent is blown off by an air blast.This leaves an aqueous colloidal dispersion slurry of the polymericmaterial, which may be applied to the paper so as to leave a surfaceresidue, or the slurry may be applied to paper at the size-press stationof a paper-making machine by roller. In another method of making apolymer-sensitized sheet, the water-insoluble polymer is ground to thedesired particle size in a ball mill with water, preferably with adispersing agent, such as a small quantity of sodium silicate. If abinder material of hydrophilic properties is ground with the phenolicmaterial, the binder itself may act as a dispersant. If desired, anamount of binder material of up to 40%, by weight, of the employedamount of the polymeric material may be added to the ball-milled slurryof materials, such binder materials being of the paper coating binderclass, including gum arabic, caselin, hydroxyethylcellulose, and latex(such as styrene-butadiene copolymer). If desired, oil adsorbents in theform of fullers earths may he added to the polymeric material particlesto assist in retaining, in situ, the liquid droplets to be transferredto it in data-representing configuration, for the purpose of preventingbleeding of the print.

Another way of applying the chromogenic or polymeric materialindividually to a single sheet of paper is by immersing a sheet of paperin a 1% to 10% solution of the material in an evaporable solvent.Obviously, this must be done alone for each reactant, because if theother reactant material were present, it would result in a prematurecoloration over the sheet area. A dried sheet with one component thenmay be coated with a solution of the other component, the solvent ofwhich is a non-solvent to the already supplied component.

The polymeric material may be dissolved in ink composition vehicles toform a printing ink of colorless character and, thus, may 'be used tospot-print a proposed record sheet unit sensitized for recording in areaction-produced color in those areas by application of a solution ofthe chromogenic material.

In the case of phenolic polymer, a printing ink may be made of up to 75%weight, of the phenolic polymeric material in a petroleum solvent to aviscosity suitable for printing purposes. The relative amounts ofcomponents to be used are the most convenient and economical amountsconsistent with proper visibility of the recorded data. The resolutionof the recorded data is, among other things, dependent on particle size,distribution and amount of particles, liquid solvent migration, chemicalreaction efliciency, and other factors, all of which are things that maybe worked out empirically by one familiar with the art, and which do notdetermine the principle of the invention, which, in part, involves meansfor enabling the bringing into solution, by marking pressure, of twonormally solid components in a common liquid solvent component heldisolated as liquid droplets, preferably in marking-pressure-rupturablecapsules having film walls, or else held isolated in a continuousmarking-pressure-rupturable film as a discontinuous phase.

In the base-acid color system of this invention this acidic mark-formingcomponent(s) reacts with the basic chromogenic material(s) to effectdistinctive color formation or color change. In a multi-sheet system inwhich an acidic organic polymer is employed, it is desirable to includeother materials to supplement the reactants. For example, kaolin can beadded to improve the transfer of the liquid and/or the dissolvedmaterials between the sheets. In addition, other materials such asbentonite, attapulgito, talc, feldspar, halloysite, magnesiumtrisilicate, silca gel, pyrophyllite, zinc sulfate, zinc sulfide,calcium sulfate, calcium citrate, calcium phosphate, calcium fluoride,barium sulfate and tannic acid can be included.

Various methods known to the prior art and disclosed in theaforementioned application S.N. 392,404 to Miller et al. and U.S. patentapplication S.N. 420,193 to Phillips et al., now U.S. Pat. No.3,455,721, can be employed in coating compositions of the mark-formingmaterials into their supporting sheets. An example of the compositionswhich can be coated onto the surface of an underlying sheet of atwo-sheet system to react with the capsule coating on the underside ofan overlying sheet is as follows.

Coating composition: Percent by wt.

Phenolic polymer mixture 17 Paper coating kaolin (white) 57 Calciumcarbonate l2 Styrene butadiene latex 4 Ethylated starch 8 Gum arabic 2EXAMPLE I The preparation of 3,3-bis-(1,2-dimethylindol-3-yl)-5-dimethylaminophthalide was conducted as follows:

14.3 grams of 1,2-dimethylindole, 9.6 grains of 4-dimethylaminophthalicanhydride, and 50 milliliters of benzene were stirred in a flask cooledin an ice bath. 16 grams of aluminum chloride was slowly added. Thestirring was continued for forty minutes, thereafter the reactionmixture was maintained at a temperature of 45 C. in a water bath for twohours.

After cooling the reaction mixture to room temperature, the benzenesolvent was removed by extraction with absolute ether. The solidmaterial remaining the the flask was dissolved in 500 milliliters of ahot 3 normal hydrochloric acid solution. Upon cooling, 3-(2-carboxy-5dimethylaminobenzoyl) 1,2 dimethylindole having the structural formula:

separated out as a precipitate exhibiting a weight of 14.2 grams.

The solution was neutralized, with ammonium hydroxide to a pH of 1; aprecipitate was formed which was discarded. Upon further neutralizationto a pH of 2.8, a second keto-acid, 3-(2-carboxy-4dimethylaminobenzoyl)-l,2-dimethylindole having the structural formula:

and exhibiting a weight of 0.85 gram was isolated out of the solution.

The synthesis of the 3,3-bis-(1,2-dimethylindol-3-yl)-S-dimethylaminophthalide was effected by the following procedure:

0.5 gram of 3-(2-carboxy 4'-dimethylaminobenzoyl)- 1,2-dimethylindoleprepared in the foregoing procedure was heated with 0.3 gram of1,2-dimethylindole in 10 milliliters of acetic anhydride to the boilingpoint of the mixture for 5 to 10 minutes. The reaction mixture washydrolyzed with water, made alkaline with sodium hydroxide to a pH ofabout 12, and extracted with benzene. From the benzene extract 3,3-bis-(l,2-dimethylindol-3-yl)- S-dimethylaminophthalide was isolated andpurified; the product exhibited a melting point of 298 C. and a weightof 0.27 gram. When a benzene solution of the product was contacted withattapulgite clay coated on paper and with a phenolic resin coated onpaper, a red color was observed.

EXAMPLE 11 3,3 bis (1,2 dimethylindol-3-yl) G-dimethylaminophthalide wasprepared according to the procedure of Example I using the secondketo-acid 3-(2-carboxy-4- dimethylaminobenzoyl)-l,2 dimethylindole whichwas prepared but not used in the conduct of Example I was used insteadof the keto-acid of Example I. The purified product exhibited a meltingpoint above 300 C.

When the 3,3 bis (1,2-dimethylindol-3-yl)-6-dimethylaminophthalideproduct in benzene solution was applied to paper coated with attapulgiteclay and paper coated with a phenolic polymer vivid red colors wereproduced.

EXAMPLE III The preparation of the compounds3,3-bis-(9-ethylcarbazol-3-yl)-5-dimethylaminophthalide and 3,3 bis (9-ethy1carbazol-3-yl)-6 dimethylaminophthalide was conducted as follows:

23.4 grams of 9-ethylcarbazole was mixed with 7.64 grams of4-dimethylaminophthalic anhydride and heated on an oil bath at C. Themixture appeared to be fluid; 12.0 grams of aluminum chloride was addedslowly. The oil bath temperature was increased to C. over a period oftwenty minutes, whereupon the reaction mixture solidified. Sixtymilliliters of benzene was added during a time increment of one hundredeighty minutes after which 25.0 grams of 1,2-dimethylindole was added tothe reaction mixture; followed by stirring for thirty minutes. Anadditional quantity of 5 milliliters of acetic anhydride was added tothe reaction mixture. The oil bath was removed (the temperature of theoil bath had been increased to 105 C.) and the reaction mixture wasstirred while it cooled. The reaction mixture was decomposed with a 3normal solution of hydrochloric acid; benzene was added to the reactionmixture and the acid was neutralized with sodium hydroxide. A benzenelayer formed and was separated from a black resinous material in anaqueous layer.

A black resinous material 3,3-bis-(9-ethylcarbazol-3-yl)-S-dimethylaminophthalide and 3,3-bis (9 ethylcarbazol 3 yl) 6dimethylaminophthalide was isolated and purified. The white, solidproduct exhibited a weight of .18 grams and a melting point range of 187to 190 C. A solution of the product in benzene appeared purple whencontacted with attapulgite clay coated on paper or with a phenolicpolymer coated on paper.

EXAMPLE IV The preparation of 3,3-bis-(2-phenylindol-3-yl)-5-dimethylaminophthalide and 3,3 bis (2 phenylindol-3-yl)-6-dimethylaminophthalide was conducted as follows:

5.8 grams of Z-phenylindole, 5.7 grams of 4-dimethylaminophthalicanhydride, and 40 milliliters of benzene were stirred in a 100milliliter flask under ice-cooling. 18.8 grams of aluminum chloride wereslowly added. After the addition of 0.5 gram of aluminum chloride, theaddition was stopped momentarily until the reaction mixture becamefluid. After stirring for 180 minutes the contents of the flask weresemi-solid.

The semi-solid complex was decomposed using 100 milliliters of 3 normalhydrochloric acid to yield a solid. The solid was treated with 300milliliters of dilute ammonium hydroxide, the mixture heated to boilingand then the hot mixture was filtered. The filtrate was acidified and agreen oil separated into a layer. The oil was stirred with an excess ofwater and a yellow solid precipitate was obtained. The yellow solidprecipitate was boiled in 200 milliliters of benzene to purify theintermediate of any entrained starting materials. A yellow insolubleintermediate product exhibited a weight of 7.1 grams. The intermediatewas a mixture of 2-carboxy-5-dimethylaminobenzoyl-Z-phenylindole and 2'carboxy 4 dimethylaminobenzoyl-2- phenylindole.

The intermediate prepared in the foregoing procedure was used in thesynthesis of 3,3-bis-(2-phenylindol-3-yl)- S-dimethylaminophthalide and3,3 bis (2 phenylindol- 3-y1)-6-dimethylaminophthalide. 1.9 grams of2-carboxy- 5-dimethylaminobenzoyl-Z-phenylindole, 0.96 gram of 2-phenylindole, and milliliters of acetic anhydride were stirred andheated on a hot plate for minutes. A precipiate formed which wasfiltered from solution. A filtrate was poured into 150 milliliters ofwater; the mixture thus formed was made alkaline with ammoniumhydroxide. A precipitate from the latter mixture was formed, separatedfrom the liquid, dissolved in benzene and precipitated with petroleumether. The solid material on further purification yielded a productexhibiting a weight of 100 milligrams and a melting point of about 200C. A solution of the 3,3-bis-2-phenylindole-3 yl) 5dimethylaminophthalide and 3 ,3-bis- (2-phenylindole-3-yl)-6-dimethylaminophthalide in benzene appeared blue when contacted withattapulgite coated on paper and blue when contacted with a phenolicpolymer coated on paper.

EXAMPLE V The compounds3-(1,2-dimethylindol-3-yl)-3-(9-ethylcarbazol-3-yl)-S-dimethylaminophthalideand 3-( 1,2 dimethylindol-3-yl)-3-(9-ethylcarbazol-3-yl) 6dimethylaminophthalide were prepared in the following procedure:

23.4 grams of 9-ethylcarbazole was mixed with 7.64 grams of4-dimethylaminophthalic anhydride and heated on an oil bath at 80 C.When the mixture appeared to be fluid, 12.0 grams of aluminum chloridewas slowly added. The temperature of the oil bath was slowly raised to110 C.; and after twenty minutes the reaction mixture solidified. A 60milliliter quantity of benzene was added to the solidified reactionmixture over a time interval of 180 minutes, after which 25.0 grams of1,2-dimethylindole was added. After stirring for 30 minutes the mixturewas fluid and an additional 5 milliliters of acetic anhydride was added.The temperature of the oil bath was raised to 105 C., whereupon the oilbath was removed and the flask allowed to cool while being stirred for30 minutes. The reaction mixture was decomposed with a 3 normal solutionof hydrochloric acid; benzene was added to the reaction mixture and theacid was neutralized with sodium hydroxide. A benzene layer formed andwas separated from a black resinous material in an aqueous layer. Aproduct was isolated and purified by chromatography. The white solidproduct, melting at 294 C., exhibited a weight of 40 milligrams. Asolution of the product in benzene appeared to turn red when contactedwith attapulgite clay coated on paper and also red when contacted with aphenolic polymer coated on paper.

EXAMPLE VI Preparation of 3,3-bis-( l-methyl-2-phenylindol-3-yl)-5-dimethylaminophthalide and 3,3-bis-(1-methyl-2phenylindol-3-yl)-6-dimethylaminophthalide.

4.1 grams of I-methyl-Z-phenylindole, 3.8 grams of 4-dimethylaminophthalic anhydride and 30 milliliters of benzene werestirred in a milliliter flask under icecooling, 2.9 grams of anhydrousaluminum chloride was added slowly. Stirring was continued at 5l4 C. forone hour, and 5070 C. for another hour. Petroleum ether was employed toextract the benzene and thereupon leaving a solid. The solid wasdecomposed with 200 milliliters of water, the precipitate thus formedbeing removed by filtration. The precipitate was dissolved in 200milliliters of 5 N ammonium hydroxide and filtered. The filtrate uponneutralization with dilute hydrochloric acid to a pH of about 3 yieldedthe following isomeric acids, A and B weighing 4.3 grams:

The crude isomeric acids, without further purification, were reactedwith l-methyl-Z-phenylindole in the presence of acetic anhydride as inExample I. The product, a mixture of bis-( l-methyl-Z-phenylindol 3 yl)5 dimethylaminophthalide and bis-(1-methyl-2-phenylindol-3-yl)-6-dimethylaminophthalide was chromatographed employing an alumina column.Solution of the product in benzene imparted a blue-purple to bothattapulgite clay coated on paper and phenolic resin coated on paper.

What is claimed is:

1. A pressure sensitive record unit comprising:

(a) support web or sheet material,

(b) mark-forming components and a pressure-releasable liquid solvent forsaid mark-forming components arranged in contiguous juxtaposition andsupported by said sheet material,

(0) at least one of the mark-forming components being maintained inisolation from the other mark-forming components prior to the pressurerelease of the solvent, and

(d) said'mark-forming components comprising at least one chromogenicmaterial of the structure:

where mimex2 k/ are selected from the group consisting of mono anddisubstituted indolyl radicals having the structural formula:

and carbazolyl radicals having the structural formula:

42 H. 7| \w w where R R and R consist of alkyl from one to four carbonatoms, phenyl, and hydrogen; where Y and Z consist of hydrogen anddialkylamino which the alkyl substituents have from one to four carbonatoms, providing that one of Y and Z must be hydrogen and the other mustbe said dialkylamino and an electron-accepting material of the Lewisacid type reactive with said chromogenic material to produce a mark;which components upon pressure-release of the liquid solvent are broughtinto reactive contact in the released solvent,

2. The record unit of claim 1 wherein the liquid solvent is present asthe nucleus of a microcapsule.

3. The record unit of claim 1 wherein the chromogenic material isdissolved in the isolated liquid solvent prior to pressure release.

4. The record unit of claim 1 wherein the markforming components and theisolated liquid solvent are present in a single support sheet.

5. The record unit of claim 1 wherein at least one member selected fromthe group consisting of the markforming components and the liquidsolvent is present in a support sheet other than the support sheethaving the remaining members of the group.

6. The record sheet material of claim 1 where the electron-acceptingmaterial of the Lewis acid type comprises a clay.

7. The record sheet material of claim 1 where the electron-acceptingmaterial of the Lewis acid type comprises at least one organic polymer.

8. The record sheet of claim 7 wherein the organic polymer is a phenolicpolymer.

9. The record sheet material of claim 1 where the chromogenic materialincludes the compound 3,3-bis- 1,2-dimethylindol-3-yl)-5-dimethylaminophthalide.

10. The record sheet material of claim 1 where the chromogenic materialincludes the compound 3,3-bis- (1,2-dimethylindol-3-yl)-6-dimethylaminophthalide.

11. The record sheet material of claim 1v where the chromogenic materialincludes the compound 3,3-bis- (9-ethylcarbazol-3 -yl) -5-dimethy1aminophthalide.

12. The record sheet material of claim 1 where the chromogenic materialincludes the compound 3,3-bis-(9-ethylcarbazol-3-yl)-6-dimethylaminqphthalide.

13. The record sheet material of claim 1 where the chromogenic materialincludes the compound 3,3-bis- (Z-phenylindol-B-yl-5-dimethylaminophthalide.

14. The record sheet material of claim 1 where the chromogenic materialincludes the compound 3,3-bis- (2-phenylindol-3-yl-6-dimethylaminophthalide.

15. The record sheet material of claim 1 where the chromogenic materialincludes the compound 3,3-bis- 1-methyl-2-phenylindol-3-yl)-5-dimethylaminophthalide.

16. The record sheet material of claim 1 where the chromogenic materialincludes the compound 3,3 bis- 1-methyl-2-phenylindol-3-yl-6-dimethylaminophthalide.

17. The record sheet material of claim 1 Where the chromogenic materialincludes the compound3-(1,2-dimethylindol-3-yl)-3-,(9-ethylcarbazol-3-yl) -5dimethylaminophthalide.

18. The record sheet material of claim 1 where the chromogenic materialincludes the compound3-(1,2-dimethylindol-3-yl)-3-(9-ethylcarbazol-3-yl) 6dimethylaminophthalide.

19. A mark-forming manifold, comprising: a first web or sheet having onone surface a transfer coating which contains as a finely dispersedphase a plurality of minute, pressure-rupturable, capsules containing asan inner phase a solvent vehicle; a second web or sheet having anadherent coating upon its surface or dispersed within said web or sheet,said first and second webs or sheets being maintained disposed togetherin face-to-face relationship with said respective transfer and adherentcoatings in contiguity with each other; one coating con stituent in theform of a substantially colorless or slightly colored chromogenicmaterial which includes as a major functional arrangement the molecularstructure:

@ N1 and -CN2 are selected from the group consisting of mono anddisubstituted indolyl having the structural formula:

and carbazolyl having the structural formula:

and Y must be hydrogen and the other must be said dialkylamino; andanother constituent consisting of an electron-accepting material of theLewis acid type; one of said constituents being dissolved in saidsolvent liquid vehicle present as the inner phase of the plurality ofminute pressure-rupturable capsules in the transfer coating on or withinsaid first web or sheet, and the other of said coating constituentsbeing bonded to said second web in said adherent coating thereon butbeing accessible to other materials coming into contact with portions ofthe adherent coating, whereby upon local impact and rupture of saidcapsules, releasing said liquid vehicle containing one coatingconstituent from at least some of the capsules onto said contiguousadherent coating, reactive contact is effected between said twoconstituents to produce a dark-colored material by the action of saidelectron-accepting material of the Lewis acid type upon said chromogenicmaterial to effect color change on said chromogenic compound.

20. The mark-forming manifold of claim 19 in which theelectron-accepting material of the Lewis acid type comprises a clay.

21. The mark-forming manifold of claim 19 in which theelectron-accepting material of the Lewis acid type comprises an organicpolymer.

22. The mark-forming manifold of claim 19 in which theelectron-accepting material of the Lewis acid type comprises a phenolicpolymer.

23. The mark-forming manifold of claim 19 in which at least onechromogenic compound is 3,3-bis-(l,2-dimethylindol-3 -yl)--dimethylaminophth alide.

24. The mark-forming manifold of claim 19 in which at least onechromogenic compound is 3,3-bis-(l,2-di methylindol-S-yl)-6-dimethylaminophthalide.

25. The mark-forming manifold of claim 19 in which at least onechromogenic compound is 3,3-bis- (9-ethylcarb azol-3 -yl-5-dimethylaminophthalide.

26. The mark-forming manifold of claim 9 in which at least onechromogenic compound is 3,3-bis-(9-ethy1carbazol-3 -yl)-6-dimethylaminophthalide.

27. The mark-forming manifold of claim 19 in which at least onechromogenic compound is3,3-bis-(2-phenylindol-3-yl)-S-dimethylaminophthalide.

28. The mark-forming manifold of claim 19 in which at least onechromogenic compound is3,3-bis-(2-phenylindol-3-yl)-6-dimethylaminophthalide.

29. The mark-forming manifold of claim 19 in which at least onechromogenic compound is 3,3-bis-(l-methyl- 2-phenylindol-3-yl-5-dimethylaminophthalide.

30. The mark-forming manifold of claim 19 in which at least onechromogenic compound is 3,3-bis-(1-methyl- 2-phenylindol-3 -yl-6-dimethyl amino phthalide.

31. The mark-forming manifold of claim 19 in which at least onechromogenic compound is3-(1,2-dimethylindol-3-yl)-3-(9-ethylcarbazol-3-yl) 5dimethylaminophthalide.

32. The mark-forming manifold of claim 19 in which at least onechromogenic compound is3-(1,2-dimethylindol-3-yl)-3-(9-ethylcarbazol-3-yl) 6dimethylaminophthalide.

33. The method of marking on a substrate by developing dark-coloredmaterials from chromogenic compounds comprising: providing as at leastone constituent a colorless or slightly colored chromogenic compoundhaving the structural formula:

{ 91 and 02 where are selected from the group consisting of mono anddisubstituted indolyl radicals having the structural formula:

where R R and R consist of alkyl having from one to four carbon atoms,phenyl, and hydrogen; Where Z and Y consist of dialkylarnino where thealkyl substituents have from one to four carbon atoms providing that oneof Z and Y must be hydrogen and the other must be said dialkylamino andbringing said chromogenic compound into contact, in areas on saidsubstrate sheet where marking is desired, with an electron-acceptingmaterial of the Lewis acid type to produce marks in said areas of adarkcolored material formed by the action of said electronacceptingmaterial on said chromogenic compound.

34. The method of claim 33 in which the electron-accepting material ofthe Lewis acid type comprises a clay.

35. The method of claim 33 in which the electronaccepting material ofthe Lewis acid type comprises an organic polymer.

36. The method of claim 33 in which the electronaccepting material ofthe Lewis acid type comprises a phenolic polymer.

37. The method of claim 33 in which at least one chromogenic compound is3,3-bis-(1,2-dimethylindol-3- yl -5-dimethylaminophthalide.

38. The method of claim 33 in which at least one chromogenic compound is3,3-bis-(1,2-dimethylindol-3- yl) -6-dimethylaminophthalide.

39. The method of claim 33 in which at least one chromogenic compound is3,3-bis-(9-ethylcarbazol-3-yl)- 5-dimethylaminophthalide.

40. The method of claim 33 in which at least one chromogenic compound is3,3-bis-(9-ethylcarbazol-3-yl)- G-dimethylaminophthalide.

41. The method of claim 33 in which at least one chromogenic compound is3,3-bis-(2-phenylindol-3-yl) S-dimethylaminophthalide.

42. The method of claim 33 in which at least one chromogenic compound is3,3-bis-(2-phenylindol-3-yl)- 6-dimethylaminophthalide.

43. The method of claim 27 in which at least one chromogenic compound is3-(1,2-dimethylindol-3-yl)-3-(9-ethylcarbazol-3-yl)-5-dimethylaminophthalide.

44. The method of claim 33 in which at least one chromogenic compound is3-(1,2-dimethylindol-3-yl)-3- (9-ethylcarbazol-3-yl)-6-dimethylaminophthalide.

45. The method of claim 33 in which at least one chromogenic compound is3,3-bis-(l-methyl-Z-phenylindol-3-yl) -5-dimethylarninophthalide.

17 18 46. The method of claim 33 in which at least one 3,268,537 8/ 1966Gosnell et a1. chromogenic compound is 3,3-bis-(l-methyl-Z-phenyl-3,336,337 8/1967 Gosnell. ind01-3-y1)-6-dimethylaminophthalide.3,455,721 7/ 1969 Phillips et a1.

3,491,111 1/1970 Lin. References Cited UNITED STATES PATENTS 2,505,4864/1950 Green. US. Cl. X.R. 3,244,549 4/1966 Farnham et a1. 117-36.8,36.9, 155

5 MURRAY KATZ, Primary Examiner

